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Anchored LH2 Complexes in 2D Polarization Imaging.

Tubasum, Sumera LU ; Sakai, Shunsuke ; Dewa, Takehisa ; Sundström, Villy LU ; Scheblykin, Ivan LU ; Nango, Mamoru and Pullerits, Tönu LU (2013) In The Journal of Physical Chemistry Part B 117(38). p.11391-11396
Abstract
Protein is a soft material with inherently large structural disorder. Consequently, the bulk spectroscopies of photosynthetic pigment protein complexes provide averaged information where many details are lost. Here we report spectroscopy of single light-harvesting complexes where fluorescence excitation and detection polarizations are both independently rotated. Two samples of peripheral antenna (LH2) complexes from Rhodopseudomonas acidophila were studied. In one, the complexes were embedded in polyvinyl alcohol (PVA) film; in the other, they were anchored on the glass surface and covered by the PVA film. LH2 contains two rings of pigment molecules-B800 and B850. The B800 excitation polarization properties of the two samples were found to... (More)
Protein is a soft material with inherently large structural disorder. Consequently, the bulk spectroscopies of photosynthetic pigment protein complexes provide averaged information where many details are lost. Here we report spectroscopy of single light-harvesting complexes where fluorescence excitation and detection polarizations are both independently rotated. Two samples of peripheral antenna (LH2) complexes from Rhodopseudomonas acidophila were studied. In one, the complexes were embedded in polyvinyl alcohol (PVA) film; in the other, they were anchored on the glass surface and covered by the PVA film. LH2 contains two rings of pigment molecules-B800 and B850. The B800 excitation polarization properties of the two samples were found to be very similar, indicating that orientation statistics of LH2s are the same in these two very different preparations. At the same time, we found a significant difference in B850 emission polarization statistics. We conclude that the B850 band of the anchored sample is substantially more disordered. We argue that both B800 excitation and B850 emission polarization properties can be explained by the tilt of the anchored LH2s due to the spin-casting of the PVA film on top of the complexes and related shear forces. Due to the tilt, the orientation statistics of two samples become similar. Anchoring is expected to orient the LH2s so that B850 is closer to the substrate. Consequently, the tilt-related strain leads to larger deformation and disorder in B850 than in B800. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
117
issue
38
pages
11391 - 11396
publisher
The American Chemical Society (ACS)
external identifiers
  • wos:000330161700044
  • pmid:23651282
  • scopus:84884935631
  • pmid:23651282
ISSN
1520-5207
DOI
10.1021/jp403863c
language
English
LU publication?
yes
additional info
The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)
id
74a1afb9-16f3-4cc0-b8c4-fcdd50c28e86 (old id 3804808)
date added to LUP
2016-04-01 10:45:20
date last changed
2020-01-12 05:24:38
@article{74a1afb9-16f3-4cc0-b8c4-fcdd50c28e86,
  abstract     = {Protein is a soft material with inherently large structural disorder. Consequently, the bulk spectroscopies of photosynthetic pigment protein complexes provide averaged information where many details are lost. Here we report spectroscopy of single light-harvesting complexes where fluorescence excitation and detection polarizations are both independently rotated. Two samples of peripheral antenna (LH2) complexes from Rhodopseudomonas acidophila were studied. In one, the complexes were embedded in polyvinyl alcohol (PVA) film; in the other, they were anchored on the glass surface and covered by the PVA film. LH2 contains two rings of pigment molecules-B800 and B850. The B800 excitation polarization properties of the two samples were found to be very similar, indicating that orientation statistics of LH2s are the same in these two very different preparations. At the same time, we found a significant difference in B850 emission polarization statistics. We conclude that the B850 band of the anchored sample is substantially more disordered. We argue that both B800 excitation and B850 emission polarization properties can be explained by the tilt of the anchored LH2s due to the spin-casting of the PVA film on top of the complexes and related shear forces. Due to the tilt, the orientation statistics of two samples become similar. Anchoring is expected to orient the LH2s so that B850 is closer to the substrate. Consequently, the tilt-related strain leads to larger deformation and disorder in B850 than in B800.},
  author       = {Tubasum, Sumera and Sakai, Shunsuke and Dewa, Takehisa and Sundström, Villy and Scheblykin, Ivan and Nango, Mamoru and Pullerits, Tönu},
  issn         = {1520-5207},
  language     = {eng},
  number       = {38},
  pages        = {11391--11396},
  publisher    = {The American Chemical Society (ACS)},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Anchored LH2 Complexes in 2D Polarization Imaging.},
  url          = {http://dx.doi.org/10.1021/jp403863c},
  doi          = {10.1021/jp403863c},
  volume       = {117},
  year         = {2013},
}